A043188 Numbers k such that 1 and 2 occur juxtaposed in the base-9 representation of k but not of k-1.

11, 19, 92, 99, 171, 181, 254, 262, 335, 343, 416, 424, 497, 505, 578, 586, 659, 667, 740, 748, 821, 828, 891, 983, 991, 1064, 1072, 1145, 1153, 1226, 1234, 1307, 1315, 1388, 1396, 1469, 1477, 1539, 1629, 1639, 1712, 1720

Offset

1,1

Links

Table of n, a(n) for n=1..42.

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 9], {1, 2}]>0 || SequenceCount[ IntegerDigits[n, 9], {2, 1}]>0, 1, 0], {n, 2000}], {0, 1}][[All, 2]] (* Harvey P. Dale, Nov 24 2022 *)

Crossrefs

Cf. A007095.

Sequence in context: A039365 A103201 A199338 * A043968 A199329 A121132

Adjacent sequences: A043185 A043186 A043187 * A043189 A043190 A043191

Keyword

nonn,base

Author

Clark Kimberling

Status

approved